Re: 2 million lines of FORTRAN code
Actually this isn't the problem at all. Fortran is really a single-purpose language: it does high-performance, large-scale, numerical code. No-one working on a Fortran system is worrying about the performance of OS kernels, video games or database interfaces, because it isn't used for that: all they have to worry about is getting large-scale numerical codes to run, really fast. And there are people who have a lot of money to spend on this – the kind of people who are interested in CFD simulations which run for millionths of a second of model time.
The end result of all this is that Fortran systems have very, very good numerical performance. C systems, empirically don't, and C++ systems don't even have support in the standard for it. Fortran is really the only game in town for this stuff, as it has always been.